The invention relates generally to marine propulsion devices, such as outboard motors and stern drive units. More particularly, the invention relates to steering mechanisms for such outboard motors and stern drive units.
In one type of prior steering mechanism, the steering arm of the marine propulsion unit was connected to a steering link extending to one side of the motor and which, at some point, was supported by the boat remotely from the propulsion device. As a result, and because the connection of the steering arm and the steering link travel in one arc in response to steering and in another arc in response to tilting, such arrangements commonly included connection of the steering link to the boat and to the steering arm by arrangements affording universal movement. In addition, tilting of the propulsion unit usually caused steering movement of the propulsion unit.
Examples of the just mentioned prior steering mechanisms are illustrated in the following patents:
Shimanekas U.S. Pat. No. 3,631,833, Jan. 4, 1972. PA1 Waner U.S. Pat. No. 3,832,967, Sept. 3, 1974. PA1 Rockhill U.S. Pat. No. 2,961,986, Nov. 29, 1960. PA1 Post U.S. Pat. No. 2,875,722, Mar. 3, 1959. PA1 Borst et al U.S. Pat. No. 3,774,568, Nov. 27, 1973. PA1 Borst et al U.S. Pat. No. 4,054,102, Oct. 18, 1977. PA1 Erling U.S. Pat. No. 2,028,089, Jan. 14, 1936. PA1 Wilkins U.S. Pat. No. 3,063,244, Nov. 13, 1962. PA1 Mills U.S. Pat. No. 3,772,996, Nov. 20, 1973.
In another previous type of steering mechanism, the steering mechanism was mounted, in part, in the tilt tube for common tilting movement with the swivel bracket. In these systems, a drag link was connected between the steering arm and a link or steering member which usually extended through the tilt tube and to one side of the installation for connection with the drag link. The connections included in these mechanisms often resulted in undesirable bending moments on the mechanism. Specifically, because the link or steering member moved in a straight line through the tilt tube, and the steering arm moved in a arc, a moment was caused by the angular relationship between the moveable member and the drag link. The linear movement of the junction between the drag link and the moveable member also made support for that member difficult.
Examples of the just mentioned prior steering mechanisms are illustrated in the following patents:
The steering mechanism described hereinafter is believed to overcome various of the disadvantages of the prior systems.
Attention is also directed to the additional following patents: